The invention pertains to a method for introducing and removing a rod assembly, such as is used for boring in the ground, in particular for producing or widening ground bores and/or for shattering old pipelines and laying new pipelines, using various tools.
It is known to produce ground bores with the aid of presses or winches by means of a static forward drive, by a rod assembly with a boring head being pushed or pulled through the ground. In the same way, old pipelines can be shattered, for example with a bursting head fixed to the rod assembly, and replaced by new pipelines.
The boring or widening heads are generally driven into the ground with the aid of a push/pull unit which is located in an excavation on the axis of the bore and acts on the rod assembly. In the case of the widespread round rod assemblies, the force from the push/pull unit is transferred via clamping jaws acting on the outer surface of the rod assembly or via an adapter which is fitted to the end of the rear rod section.
With the rod assembly described in German patent 196 08 980, a rod assembly was provided which avoids the threaded joints, which are sensitive to soiling and time-consuming to join, of the known round rod assemblies, in that a ladder-like rod section is proposed which has projections and/or recesses for positive coupling means of a forward drive unit. In addition, the rod sections have coupling means at their ends, which likewise permit the positive joining of the individual rod sections. However, the rod sections have to be joined individually and by hand by an operator, who is located for example in the starting excavation.
The European laid-open specification 0 812 976 discloses a boring rod in which the individual rod sections are joined to one another in an articulated manner and are moved into the axis of the bore via an excavation. The individual rod sections execute a change in position during this from an essentially vertical to an essentially horizontal position. The disadvantage of this method and this apparatus is that the pins which join the rod sections to one another have to be hammered individually into the connecting holes provided for the purpose when the rod assembly is assembled, and have to be hammered out of the holes during the removal of the rod sections. Although this permits automatic feeding of a rod assembly from the surface of the ground, it requires a considerable expenditure in terms of time and force when joining the rod sections. Under the conditions of the building site, such pin connections also often become dirty and thus difficult to operate.
Starting from this point, the invention is based on the object of providing a method for automatically joining and/or detaching rod sections.
The invention is based on the idea of producing mutual engagement between rod sections, for example of the type described in German patent 196 08 980, by means of a specific geometric arrangement and rotation about an axis located essentially perpendicular to the axis of the rod sections, and of detaching rod sections from one another.
The invention is also based on the object of providing an apparatus for automatically detaching and joining rod sections.
The objects are achieved by the independent claims. Configurations are to be taken from the subclaims.
With the aid of the method of the invention, a rod connection can be made without the presence of an operator, for example in a narrow shaft. This is particularly advantageous in the case of sewage shafts, which normally have a diameter of only 1 meter. This small diameter does not permit the simultaneous presence of an operator when there is already a push/pull unit in the shaft. Using the apparatus of the invention and the method of the invention, the rod sections can be fed from the surface of the roadway, especially with the aid of a guide element, preferably a feed tube, to the axis of the bore and therefore to the boring rod assembly. At the same time, natural gravity preferably has the effect that the inserted rod sections slide further, the rotation according to the invention effecting automatic coupling of the ends of the rod sections.
With the aid of the method of the invention, it is likewise possible for detachment of the rods to be carried out without the presence of an operator. Instead of natural gravity, in this case the pressure exerted by the push/pull apparatus on the rod assembly acts on the latter as it is withdrawn from the bore. In this case, the rod sections, when they reach a specific position in the excavation, can be levered out of the axis of the bore, by a specific angle, using pressure, spring force or lever force. The angle is then selected such that as the rod is displaced further in relation to the levered-out rod section, for example on a guide element or pipe, the force exerted by the push/pull unit is converted into a rotation about a point perpendicular to the axis of the rod section. If a guide pipe is used, the rod sections can be pushed to the surface of the ground one after another in this way and can be removed there. As already described, the rods can be pushed one after another to the surface of the ground. However, it may also be the case that the rods are conveyed to the surface of the ground by a conveying mechanism by a guide pipe, a guide rail or the like. If the rod sections have extensions or recesses, the conveying mechanism can preferably act on these extensions or recesses and convey the rods. In a preferred design, the conveying mechanism is driven by the push/pull carriage, optionally via a link mechanism.
In a special embodiment, however, the drive could also have a separate drive, it then being necessary for the drives to be coordinated with each other, which would make the matter more complicated.
In the preferred embodiment, it is finally possible to say again that the drive for conveying the rods in and conveying the rods out is carried out via the carriage. (advance carriage) of the push/pull unit, that is to say ultimately via the drive of the latter. No separate drive would be needed for the rod transport.
The transmission of force is primarily carried out from the drive to the rod via flat link mechanisms, which can also be operated with spring assistance.
The guide element can be magnetic and/or can comprise a guide pipe made of individual pluggable pipe elements, and can be fixed to the push/pull unit. For reasons of weight, the guide element may also be of lattice design.
The push/pull unit is preferably operated via two cylinders. The two cylinder chambers of the push/pull unit can each be connected to a pressure source via a hydraulic line each with a xc2xe-way valve, between which there is connected a changeover valve with a manometer which measures the respective current pressure and which, when the maximum pressure is reached, switches the xc2xe-way valve via a controller and, in so doing, connects one or the other hydraulic line to the pressure source.
This permits automatic operation of the advance carriage, so that the entire apparatus is completely automated. In addition, damage can be avoided if the apparatus is set for a maximum thrust and/or pulling pressure, so that the apparatus is automatically switched off if it encounters an unexpected obstacle in the ground.
The rod feed and removal system of the invention has considerable safety advantages, since crush injuries of an operator in the shaft caused by a rod emerging from the bore in the shaft are ruled out.
Furthermore, the invention is also suitable for use with an automatic rod store, such as a rod magazine, which can be positioned on the surface of the ground and, accordingly, does not have to be matched in size to the shaft size, like conventional rod magazines. When an automatic rod magazine is used for accommodating and dispensing rods, the entire unit can be operated by a single person, who merely has to control the forward drive unit and can remain at any desired point, for example in the target shaft.